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Simultaneous enhancement of efficiency and stability of OLEDs with thermally activated delayed fluorescence materials by modifying carbazoles with peripheral groups

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Abstract

Albeit their high efficiencies, the operational stability of the organic light emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) emitters is still far from satisfaction, and few strategies have been proposed to improve their stability. Here, we show that by modifying the carbazole unit, one of the most commonly used donors in TADF emitters, with peripheral groups, both the device efficiency and operational stability can be greatly improved. A well-known TADF molecule— 4,5-di(9H-carbazol-9-yl)phthalonitrile (2CzPN) was chosen as the prototype and modified by introducing peripheral tert-butyl and phenyl groups to the 3,6-positions of the carbazole (named 2tBuCzPN and 2PhCzPN, respectively). The introduced groups not only improve the compounds’ electrochemical stabilities referred to the cyclic voltammetry multi-sweep results, but also promote their photoluminescence quantum yields. Furthermore, reduced singlet-triplet energy gaps are observed, leading to the shortened exciton lifetimes which are benefit to suppress the exciton annihilations. Besides, the steric hindrance of introduced phenyl groups can partly restrain the concentration quenching of the TADF emitter. Consequently, OLEDs based on 2tBuCzPN and 2PhCzPN achieved improved maximum external quantum efficiencies (EQEs) of 17.0% and 14.0%, respectively (compared to 8.5% for 2CzPN). Meanwhile, 2PhCzPN based OLED showed reduced roll-off characteristics and a longer lifetime of 7.8 times higher than that of 2CzPN, testifying the effectiveness of subtle modification of the unstable moieties in simultaneous enhancement of efficiency and stability of OLEDs based on TADF emitters.

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References

  1. Adachi C. Jpn J Appl Phys, 2014, 53: 060101

    Article  CAS  Google Scholar 

  2. Tao Y, Yuan K, Chen T, Xu P, Li H, Chen R, Zheng C, Zhang L, Huang W. Adv Mater, 2014, 26: 7931–7958

    Article  CAS  PubMed  Google Scholar 

  3. Jou JH, Kumar S, Agrawal A, Li TH, Sahoo S. J Mater Chem C, 2015, 3: 2974–3002

    Article  CAS  Google Scholar 

  4. Yang Z, Mao Z, Xie Z, Zhang Y, Liu S, Zhao J, Xu J, Chi Z, Aldred MP. Chem Soc Rev, 2017, 46: 915–1016

    Article  CAS  PubMed  Google Scholar 

  5. Su SJ. Chin Sci Bull, 2016, 61: 3448–3452 (in Chinese)

    Article  Google Scholar 

  6. Endo A, Sato K, Yoshimura K, Kai T, Kawada A, Miyazaki H, Adachi C. Appl Phys Lett, 2011, 98: 083302

    Article  CAS  Google Scholar 

  7. Uoyama H, Goushi K, Shizu K, Nomura H, Adachi C. Nature, 2012, 492: 234–238

    Article  CAS  PubMed  Google Scholar 

  8. Rizzo F, Cucinotta F. Isr J Chem, 2018, 58: 874–888

    Article  CAS  Google Scholar 

  9. Dias FB, Bourdakos KN, Jankus V, Moss KC, Kamtekar KT, Bhalla V, Santos J, Bryce MR, Monkman AP. Adv Mater, 2013, 25: 3707–3714

    Article  CAS  PubMed  Google Scholar 

  10. Nishimoto T, Yasuda T, Lee SY, Kondo R, Adachi C. Mater Horiz, 2014, 1: 264–269

    Article  CAS  Google Scholar 

  11. Kawasumi K, Wu T, Zhu T, Chae HS, van Voorhis T, Baldo MA, Swager TM. J Am Chem Soc, 2015, 137: 11908–11911

    Article  CAS  PubMed  Google Scholar 

  12. Cho YJ, Yook KS, Lee JY. Adv Mater, 2014, 26: 6642–6646

    Article  CAS  PubMed  Google Scholar 

  13. Hatakeyama T, Shiren K, Nakajima K, Nomura S, Nakatsuka S, Kinoshita K, Ni J, Ono Y, Ikuta T. Adv Mater, 2016, 28: 2777–2781

    Article  CAS  PubMed  Google Scholar 

  14. Nishide J, Nakanotani H, Hiraga Y, Adachi C. Appl Phys Lett, 2014, 104: 233304

    Article  CAS  Google Scholar 

  15. Cho YJ, Jeon SK, Chin BD, Yu E, Lee JY. Angew Chem Int Ed, 2015, 54: 5201–5204

    Article  CAS  Google Scholar 

  16. Lee SY, Adachi C, Yasuda T. Adv Mater, 2016, 28: 4626–4631

    Article  CAS  PubMed  Google Scholar 

  17. Lee SY, Yasuda T, Komiyama H, Lee J, Adachi C. Adv Mater, 2016, 28: 4019–4024

    Article  CAS  PubMed  Google Scholar 

  18. Zhang Y, Zhang D, Cai M, Li Y, Zhang D, Qiu Y, Duan L. Nanotechnology, 2016, 27: 094001

    Article  CAS  PubMed  Google Scholar 

  19. Sun JW, Lee JH, Moon CK, Kim KH, Shin H, Kim JJ. Adv Mater, 2014, 26: 5684–5688

    Article  CAS  PubMed  Google Scholar 

  20. Kaji H, Suzuki H, Fukushima T, Shizu K, Suzuki K, Kubo S, Komino T, Oiwa H, Suzuki F, Wakamiya A, Murata Y, Adachi C. Nat Commun, 2015, 6: 8476

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  21. Lin TA, Chatterjee T, Tsai WL, Lee WK, Wu MJ, Jiao M, Pan KC, Yi CL, Chung CL, Wong KT, Wu CC. Adv Mater, 2016, 28: 6976–6983

    Article  CAS  PubMed  Google Scholar 

  22. Cui LS, Nomura H, Geng Y, Kim JU, Nakanotani H, Adachi C. Angew Chem Int Ed, 2017, 56: 1571–1575

    Article  CAS  Google Scholar 

  23. Kuei CY, Tsai WL, Tong B, Jiao M, Lee WK, Chi Y, Wu CC, Liu SH, Lee GH, Chou PT. Adv Mater, 2016, 28: 2795–2800

    Article  CAS  PubMed  Google Scholar 

  24. Shin H, Lee JH, Moon CK, Huh JS, Sim B, Kim JJ. Adv Mater, 2016, 28: 4920–4925

    Article  CAS  PubMed  Google Scholar 

  25. Shizu K, Noda H, Tanaka H, Taneda M, Uejima M, Sato T, Tanaka K, Kaji H, Adachi C. J Phys Chem C, 2015, 119: 26283–26289

    Article  CAS  Google Scholar 

  26. Lee SY, Yasuda T, Park IS, Adachi C. Dalton Trans, 2015, 44: 8356–8359

    Article  CAS  PubMed  Google Scholar 

  27. Tsang DPK, Matsushima T, Adachi C. Sci Rep, 2016, 6: 22463

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  28. Kim M, Jeon SK, Hwang SH, Lee JY. Adv Mater, 2015, 27: 2515–2520

    Article  CAS  PubMed  Google Scholar 

  29. Lee J, Aizawa N, Numata M, Adachi C, Yasuda T. Adv Mater, 2017, 29: 1604856

    Article  CAS  Google Scholar 

  30. Zhang D, Cai M, Zhang Y, Zhang D, Duan L. Mater Horiz, 2016, 3: 145–151

    Article  CAS  Google Scholar 

  31. Noda H, Nakanotani H, Adachi C. Sci Adv, 2018, 4: eaao6910

    Google Scholar 

  32. Masui K, Nakanotani H, Adachi C. Org Electron, 2013, 14: 2721–2726

    Article  CAS  Google Scholar 

  33. Kondakov DY. J Appl Phys, 2008, 104: 084520

    Article  CAS  Google Scholar 

  34. Schmidbauer S, Hohenleutner A, König B. Adv Mater, 2013, 25: 2114–2129

    Article  CAS  PubMed  Google Scholar 

  35. So F, Kondakov D. Adv Mater, 2010, 22: 3762–3777

    Article  CAS  PubMed  Google Scholar 

  36. Lin N, Qiao J, Duan L, Wang L, Qiu Y. J Phys Chem C, 2014, 118: 7569–7578

    Article  CAS  Google Scholar 

  37. Hong M, Ravva MK, Winget P, Brédas JL. Chem Mater, 2016, 28: 5791–5798

    Article  CAS  Google Scholar 

  38. Xiang C, Fu X, Wei W, Liu R, Zhang Y, Balema V, Nelson B, So F. Adv Funct Mater, 2016, 26: 1463–1469

    Article  CAS  Google Scholar 

  39. Karon K, Lapkowski M. J Solid State Electrochem, 2015, 19: 2601–2610

    Article  CAS  Google Scholar 

  40. Carlier R, Raoult E, Tallec A, Andre V, Gauduchon P, Lancelot JC. Electroanalysis, 1997, 9: 79–84

    Article  CAS  Google Scholar 

  41. Majeed SA, Ghazal B, Nevonen DE, Goff PC, Blank DA, Nemykin VN, Makhseed S. Inorg Chem, 2017, 56: 11640–11653

    Article  CAS  PubMed  Google Scholar 

  42. Tuong Ly K, Chen-Cheng RW, Lin HW, Shiau YJ, Liu SH, Chou PT, Tsao CS, Huang YC, Chi Y. Nat Photon, 2017, 11: 63–68

    Article  CAS  Google Scholar 

  43. Chan CY, Tanaka M, Nakanotani H, Adachi C. Nat Commun, 2018, 9: 5036

    Article  CAS  PubMed  PubMed Central  Google Scholar 

Download references

Acknowledgements

This work was supported by the National Key Research and Development Program of China (2017YFA0204501), and the National Science Fund of China (51525304, 61890942, U1601651).

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Authors and Affiliations

  1. Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China

    Yunge Zhang, Dongdong Zhang, Yong Qiu & Lian Duan

  2. Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, China

    Taiju Tsuboi

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  1. Yunge Zhang
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  2. Dongdong Zhang
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  3. Taiju Tsuboi
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  4. Yong Qiu
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  5. Lian Duan
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Correspondence to Lian Duan.

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Zhang, Y., Zhang, D., Tsuboi, T. et al. Simultaneous enhancement of efficiency and stability of OLEDs with thermally activated delayed fluorescence materials by modifying carbazoles with peripheral groups. Sci. China Chem. 62, 393–402 (2019). https://doi.org/10.1007/s11426-018-9413-5

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  • DOI: https://doi.org/10.1007/s11426-018-9413-5

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